Thermal collapse of SAPO-34 molecular sieve towards a perfect glass

► Collapse of a silicoaluminophosphate molecular sieve by thermal aging was studied. ► Zeolite-LDA collapse occurs in the temperature range of 1000 to 1100 °C. ► Macroscopic morphology is retained throughout amorphization and recrystallization. ► A coordination change occurs in Al-polyhedra from six-fold to four-fold. ► SiO4 tetrahedra segregate from the AlPO4 lattice to form an amorphous silica phase.